Electrical precipitator

ABSTRACT

An electrical precipitator in the shape of a cabinet of which the door supports the electrodes on its inside face. One electrode consists of a wire wound back-and-forth between projecting resilient fingers of insulative material, while the other electrode is made up of conductive plates interposed between the adjacent reaches of the wire. All the plates are in electrical communication with one another. The door closure includes a switch controlling the energization of the electrodes such that the circuit is broken immediately the door-opening procedure is initiated, and the door-opening procedure requires a number of seconds to complete, sufficient to permit the electrodes to discharge completely before the door can be swung open.

United States Patent Remick 1151 3,654,747 1451 Apr. 11, 1972 Canada [73] Assignee: Electrohome Limited [22] Filed: Dec. 11, 1969 [21] Appl. No.: 884,150

[52] US. Cl ..55/126, 55/128, 55/139, 55/146, 55/147, 55/149, 55/151, 55/154, 55/316,

[51] Int. Cl ..B03c 3/01 [58] Field ofSearch.... ..55/139, 128, 129, 136, 137, 55/138,147, 148, 150,151, 149, 154, 126, 146,

2,696,893 12/1954 Richardson... ..55/129 2,813,595 11/1957 Fields ...55/l37 2,987,137 6/1961 Brixius et al... ...55/l38 3,027,970 4/1962 Mueller ..55/1 38 3,149,937 9/1964 Revell ..55/l51 X 3,191,362 6/1965 Bourgeois ..55/l5l X 3,222,848 12/1965 Koble, Jr ..55/l39 X 3,237,382 3/1966 Berly ..55/l47 X 3,438,180 4/1969 Klouda ..55/l5l X 3,495,381 2/1970 Flanagan ..55/l38 X 3,504,482 4/1970 Goettl ..55/1 39 3,513,634 S/l970 Angonese et a1. ..55/l39 Primary Examiner-Dennis E. Talbert, Jr. Attorney-T. T. Rieder [5 7] ABSTRACT An electrical precipitator in the shape of a cabinet of which the door supports the electrodes on its inside face. One electrode consists of. a wire wound back-and-forth between projecting resilient fingers of insulative material, while the other electrode is made up of conductive plates interposed between the adjacent reaches of the wire. All the plates are in electrical communication with one another. The door closure includes a switch controlling the energization of the electrodes such that the circuit is broken immediately the door-opening procedure is initiated, and the door-opening procedure requires a number of seconds to complete, sufficient to permit the electrodes to discharge completely before the door can be swung open.

3 Claims, 2 Drawing Figures PATENTEBAPR 1 I ma INVEN'TOR.

BY J/ m- 0744006 ELECTRICAL PRECIPITATOR This invention relates to electrical precipitators of the kind adapted to clean air of dust, lint and other particles by forcing the laden air through a high-voltage electrostatic field. More particularly, this invention has to do with a self-contained precipitator unit which requires merely to be plugged into the wall.

One disadvantage of conventional precipitators of this kind has been the difficulty of gaining access to the actual electrodes for cleaning, repair, etc.

One object of this invention is to provide a cabinet-type electrical precipitator in which the electrodes are particularly easy of access.

Another object of this invention is to provide an electrode configuration having great ease of assembly and simplicity, and which can be cleaned easily without destroying or dislodging the electrodes.

A still further object of this invention is to provide a cabinet-type electrical precipitator having the electrodes mounted on a hinged door thereof, in which safety means are provided to ensure that the electrodes will be dead and completely discharged before the door can be swung open.

Accordingly, this invention provides an electrical precipitator comprising: a base member, a first electrically non-conductive plate member projecting from and fixed to said base member, a second electrically non-conductive plate member projecting from and fixed to said base member, the first and second plate members being in spaced, substantially parallel relation, the edges of the plate members remote from the base member defining a plurality of spaced fingers, the fingers of at least one plate member being resiliently deformable toward the other plate member, an electrically conductive wire wound between the fingers of the two plate members so that adjacent substantially parallel sections of said wire form a grid between the plate members, the wire being in tension and the fingers of said at least one plate member being resiliently deformed toward the other plate member by said tension, and a plurality of conductive plates arranged one between each pair of adjacent sections of said wire and spaced therefrom, all said conductive plates being in electrical communication with one another, means for applying an electrical potential between the wire and the conductive plates, and means for urging air between the wire sections and the conductive plates.

One embodiment of this invention is shown in the accompanying drawings, in which like numerals denote like parts throughout the several views, and in which:

FIG. 1 is a partly broken-away, exploded, perspective view of a cabinet-type electrical precipitator constructed in accordance with this invention; and

FIG. 2 is a partly broken-away, perspective view of the hinged door of the precipitator shown in FIG. 1, drawn to a larger scale, and showing the inside face thereof.

Looking first at FIG. 1, an electrical precipitator is seen to consist of a cabinet-shaped housing 12 including a base 14, a front panel 15, a rear panel 16, side panels 17 and a top panel 18. The top panel 18 consists of a rectangular frame 20 supporting a'rectangular grill 22.

The front panel has a rectangular opening 24 adapted to receive a hinged door 26. The rectangular opening 24 opens into an internally supported box structure 28, which is totally enclosed and separated from the rest of the interior of the housing 12, except for a circular opening 30 in a wall 31 of the box structure 28 opposite the hinged door 26.

An electrical motor 33 is adapted to drive a centrifugal impeller 34 of conventional construction. As can be clearly seen in FIG. 1, the intake for the centrifugal impeller 34 coincides with the circular opening 30 in the wall 31. The outlet 36 of the impeller 34 is directed upwardly as shown, although this is not essential. The air blown into the space between the box structure 28 and the housing 12 can exit therefrom only through the grill 22 at the top of the housing 12.

The electrodes of the electrical precipitator are located on the inside of the hinged door 26, and the construction thereof is best shown in FIG. 2 of the drawings, to which attention is now directed.

The hinged door 26 has a rectangular central opening 38, which is covered by a perforated screen 40 fixed to the outside of the hinged door 26 (the far side as seen in FIG. 2). At the side vertical edges of the central opening 38, the hinged door 26 defines two marginal portions 42 and 43, which are integral with the hinged door 26, but are bent inwardly at right angles thereto.

Fixed securely to the marginal portions 42 and 43, respectively, are a first electrically non-conductive plate member 45 and a second electrically non-conductive plate member 46. To speak more precisely, the hinged door 26 includes a framelike base member 48 of which the marginal portions 42 and 43 are integral parts, the base member 48 supporting the plate members 45 and 46 in spaced, substantially parallel relation. In the embodiment shown in FIG. 2, the plate members 45 and 46 are attached to the marginal portions 42 and 43 by threaded members 50.

The edges of the plate members 45 and 46 remote from the base member 48 define a plurality of spaced fingers 52, which in FIG. 2 are seen to be of crenelated configuration. The crenelated configuration is not essential to this invention, so long as fingers of some son are provided. In the embodiment shown, both plate members 45 and 46 are resiliently deformable toward each other, and for this reason are constructed of a resilient material such as high impact styrene.

An electrically conductive wire 54 is wound in a boustrophedonic configuration between the fingers 52 of the two plate members 45 and 46, such that adjacent substantially parallel sections of the wire 54 define a grid between the plate members 45 and 46. In the embodiment shown, the crenelated fingers 52 are arranged such that a finger on the plate member 45 is opposite a space in the plate member 46, and vice-versa, thus permitting the wire 54 to be wound such that adjacent sections of it are spaced uniformly from one another. The wire 54 is wound under a certain amount of tension such that the fingers of the plate members 45 and 46 are resiliently deformed toward one another by the tension. At the bottom of the hinged door 26, the wire 54 is attached to a terminal 56 to which an electric lead 57 is also attached. The upper end of the wire 54 is fixed to a terminal 58 which in turn is fixed to the plate member 46, and is isolated from the other electrical elements supported by the hinged door 26.

Also provided on the hinged door 26 is a plurality of conductive plates 60 arranged one between each pair of adjacent sections of the wire 54 and spaced from the sections of the wire. Each conductive plate 60 is in electrical communication with both marginal portions 42 and 43 through contact therewith, and the marginal portions 42 and 43 are made of an electrically conductive material, such as metal, as is the entire frame-like base member 48.

As shown in FIG. 2, each conductive plate 60 has an elongated rectangular shape, and is equiped with two end tabs 62 bent perpendicularly to the main portion of the plate 60. Through its end tabs 62, each conductive plate 60 is welded, bolted, or otherwise affixed to and between the marginal portions 42 and 43.

It will be noted in FIG. 2 that the conductive plates are oriented in horizontal planes, and this is the preferred arrangement. However, because dust, lint, etc. is attracted to the plates electrostatically, it tends to stick against the surface very securely, and an oblique or even vertical plate and wire arrangement would not present any problems as far as the functioning of the precipitator is concerned.

Attention is now returned to FIG. 1, which further shows an electrical plug 64 and an electrical wire 65 adapted to carry normal AC. power from a wall receptacle to a voltage doubler power supply 67 of the conventional type, having two DC. output terminals 68, one of which is grounded to the housing 12 at a terminal 70, the other of which is connected through a microswitch 72 to the wire 54. It will be noted that a lead extends from the mocroswitch 72, beneath the box structure 28, through an aperture 74 in one wall of the box structure 28, thence connecting with the electric lead 57 shown in FIG. 2.

The housing 12 of the electrical precipitator is made of 5 electrically conductive material, such as metal, and thus the grounded terminal 68 of the voltage doubler power supply 67 is electrically in communication, through the hinges 76, with the hinged door 26, and therefore with the conductive plate 60, by reason of the electrical contact between the conductive plates 60 and the marginal portions 42 and 43.

Attention is now directed to the microswitch 72, shown in FIG. 1, which includes a reciprocating button 79 biased in the outward or leftward direction, as seen in FIG. 1. When the button 79 is in its outward position, the electric lead carrying voltage to the wire 54 on the hinged door 26 is broken, completed contact being made when the button 79 is pressed inwardly or to the right in FIG. 1. When the door is in its fully closed position, the frame-like base member 48 (see F IG. 2) of the door contacts the button 79 and pushes it inwardly to complete the connection.

Because of the very high electric potential between the wire 54 and the conductive plates 60, it is desirable to prevent any possible contact between these electrodes and a person opening the hinged door 26 for several seconds after the micro switch 72 has been disconnected, because the wire 54 and the conductive plate 60 constitute, in effect, a capacitor, capable of storing and retaining an electrical charge. As soon as the contact has been broken in the microswitch 72, however, the capacitor formed by the wire 54 and the conductive plates 60 begins to discharge exponentially through a resistor and in a few seconds the voltage level is down to a level where it is no longer dangerous.

In order to prevent the hinged door 26 from being opened immediately after the microswitch 72 is disconnected, a manual threaded member 80 is provided at the edge of the hinged door 26 which is remote from the hinges 76. The threaded member 80 is fixed to the hinged door 26 in such a way that it can rotate about its axis, but cannot move axially with respect to the hinged door 26. The threaded member 80 is adapted to engage a tapped hole 81 having an inward cylindrical extension 82, also tapped. The length of the threaded member 80 is such that it requires several seconds for a person to screw the threaded member 80 sufficiently far into the tapped hold 81 for the door to come into contact with the button 79, thereby energizing the electrodes supported by the hinged door 26. Likewise, it takes an equal length of time to unscrew the threaded member 80 from the tapped hole 81, during most of which time the contact in the microswitch 72 is broken, thereby permitting sufficient time to elapse for the electrodes on the hinged door 26 to discharge.

It will be appreciated that it is not essential to this invention for the fingers of both plate members 45 and 46 to be resiliently deformable toward the other plate member. What is being achieved by making the fingers of the plate members deformable in the direction of the tension in the wire 54 is the provision of an alternating wire-plate-wire-plate construction which can easily be cleaned manually without worrying that lateral pressure against the tensioned wire 54 will greatly increase the tensile stress therein, possibly to the point of rupture. With the fingers 52 being resilient, the tensile stress in the wire 54 will not be significantly increased by lateral movement in any of the horizontal portions of the wire, because the resilient fingers 52 will yield to an increase in the tensile stress. It will be realized that this advantage would still be gained even if the fingers of only one plate member were resilient.

Referring again to FIG. I, mounted within the boxed structure 28 is a conventional filter 84. Actually, there can be provided one, two or more filters at the location shown for the filter 84, comprising, for example, a charcoal filter for odors, and an aluminum wool" filter to act as a dust collector.

With both the filter 84 and the motor 30 located within the box structure 28, it is very simple to gain access to the filter 4, to change the same, or to the motor 30 for oiling, repairs,

etc.

What is claimed is:

1.An electric precipitator comprising:

a housing,

a door hinged to the housing and including a door frame,

a first electrically non-conductive plate member projecting from and fixed to said door frame,

a second electrically non-conductive plate member projecting from and fixed to said door frame, the first and second plate members being in spaced, substantially parallel relation, the edges of the plate members remote from the base member defining a plurality of spaced fingers, the fingers of at least one plate member being resiliently deformable toward the other plate member,

an electrically conductive wire wound between the fingers of the two plate members so that adjacent substantially parallel sections of said wire form a grid between the plate members, the wire being in tension and the fingers of said at least one plate member being resiliently deformed toward the other plate member by said tension,

a plurality of conductive plates arranged one between each pair of adjacent sections of said wire and spaced therefrom, all said conductive plates being in electrical communication with one another and being mounted on said door frame, the conductive plates and the plate members being within the housing when the door is closed,

means for applying an electrical potential between the wire and the conductive plates,

means for urging air between the wire sections and the conductive plates,

and protective means on the door frame for permitting the passage of air through the door frame and for preventing external objects from contacting the plates or the wire when the door frame is closed.

2. An electrical precipitator as claimed in claim 1, in which the door when closed trips a microswitch connected into the power supply, such that the said electrical potential is applied only when the door is closed, and in which manually disengageable threaded means serve to hold the door in the closed position, the manual disengagement of the threaded means requiring a length of time sufficient to allow the electrical potential between the wire and the conductive plates to discharge.

3. An electrical precipitator as claimed in claim 1, in which said protective means is a perforated screen spanning for said door frame. 

1. An electric precipitator comprising: a housing, a door hinged to the housing and including a door frame, a first electrically non-conductive plate member projecting from and fixed to said door frame, a second electrically non-conductive plate member projecting from and fixed to said door frame, the first and second plate members being in spaced, substantially parallel relation, the edges of the plate members remote from the base member defining a plurality of spaced fingers, the fingers of at least one plate member being resiliently deformable toward the other plate member, an electrically conductive wire wound between the fingers of the two plate members so that adjacent substantially parallel sections of said wire form a grid between the plate members, the wire being in tension and the fingers of said at least one plate member being resiliently deformed toward the other plate member by said tension, a plurality of conductive plates arranged one between each pair of adjacent sections of said wire and spaced therefrom, all said conductive plates being in electrical communication with one another and being mounted on said door frame, the conductive plates and the plate members being within the housing when the door is closed, means for applying an electrical potential between the wire and the conductive plates, means for urging air between the wire sections and the conductive plates, and protective means on the door frame for permitting the passage of air through the door frame and for preventing external objects froM contacting the plates or the wire when the door frame is closed.
 2. An electrical precipitator as claimed in claim 1, in which the door when closed trips a microswitch connected into the power supply, such that the said electrical potential is applied only when the door is closed, and in which manually disengageable threaded means serve to hold the door in the closed position, the manual disengagement of the threaded means requiring a length of time sufficient to allow the electrical potential between the wire and the conductive plates to discharge.
 3. An electrical precipitator as claimed in claim 1, in which said protective means is a perforated screen spanning for said door frame. 